Finish Phase 1.2 HUD: selection wiring, command grid context, build progress bar

- Builder.DisplayName: stub property ("Builder (P{n})") for portrait label; swaps
  to real player name when MatchState lands in Phase 1.3
- HUDController: subscribe SelectionState.OnSelectionChanged in OnEnable/OnDisable;
  HandleSelectionChanged drives portrait label + grays out command grid when nothing
  is selected; Start() seeds initial state in case builder auto-selected before Start
- BuildSiteVisual: ComputeProgressNormalized() public API ([0,1], safe on any client);
  OnNetworkSpawn spawns a non-networked BuildProgressBar child
- BuildProgressBar: new world-space uGUI Canvas bar; green while Constructing, yellow
  while Paused, hidden while Queued; billboards to Camera.main each LateUpdate;
  auto-destroyed when parent BuildSiteVisual despawns

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Assets/_Project/Scripts/Gameplay/BuildSiteVisual.cs

@@ -4,6 +4,7 @@ using Unity.Netcode;
 using UnityEngine;
 using TD.Core;
 using TD.Towers;
+using TD.UI;
 
 namespace TD.Gameplay
 {
@@ -186,6 +187,20 @@ namespace TD.Gameplay
         /// <summary>Accumulated construction time (across pause/resume cycles). Used on resume.</summary>
         public float AccumulatedConstructionTime => accumulatedConstructionTime.Value;
 
+        /// <summary>
+        /// Returns [0,1] normalized construction progress. Safe to call on any client.
+        /// Returns 0 while Queued; freezes at accumulated fraction while Paused.
+        /// </summary>
+        public float ComputeProgressNormalized()
+        {
+            float bt = buildTime.Value;
+            if (bt <= 0f) return 0f;
+            float currentRunElapsed = constructionStartServerTime.Value > 0f
+                ? (float)NetworkManager.Singleton.ServerTime.Time - constructionStartServerTime.Value
+                : 0f;
+            return Mathf.Clamp01((currentRunElapsed + accumulatedConstructionTime.Value) / bt);
+        }
+
         // ----- Pre-spawn init data (server) -------------------------------
 
         private string pendingDefName;
@@ -251,6 +266,12 @@ namespace TD.Gameplay
 
             // Apply initial visual state based on the (now-replicated) values.
             ApplyStageVisual(currentStage.Value);
+
+            // Attach a local (non-networked) progress bar — each client creates its own.
+            // Destroyed automatically when this NetworkObject is despawned (it's a child).
+            var barHost = new GameObject("ProgressBar");
+            barHost.transform.SetParent(transform, false);
+            barHost.AddComponent<BuildProgressBar>().Initialize(this);
         }
 
         public override void OnNetworkDespawn()

Assets/_Project/Scripts/Gameplay/Builder.cs

@@ -156,6 +156,17 @@ namespace TD.Gameplay
         /// <summary>Maximum jobs allowed in the queue.</summary>
         public int MaxQueueDepth => settings.maxQueueDepth;
 
+        /// <summary>Display name shown in the HUD portrait. Stub until MatchState provides player names.</summary>
+        public string DisplayName
+        {
+            get
+            {
+                PlayerSlot slot = OwnerToSlot(OwnerClientId);
+                int n = (int)slot;
+                return n >= 1 && n <= 9 ? $"Builder (P{n})" : "Builder";
+            }
+        }
+
         /// <summary>True if a tile is currently part of any queued or constructing job.</summary>
         /// <remarks>
         /// Used by <c>TowerPlacementManager</c> to reject placement on tiles already